Yu. Kamyshkov

Hadron calorimetry in the L3 detector

Abstract The characteristics of the L3 hadron calorimeter as realized in the observation of hadronic jets and other events from e + e − collisions at LEP are presented and discussed. The pattern-recognition algorithm utilizing the fine granulatiry of the calorimeter is described, and the observed overall resolution of 10.2% for hadron jets from Z decay is reported. The use of the calorimeter in providing information on muon energy losses is also noted.

The parallel plate chamber as a detector for fast, radiation resistive calorimetry

We have built and tested a thin (1 mm) single gap parallel plate chamber (PPC) with planar electrodes, working in the avalanche mode. It consists of sixteen 1 mm gap cells, each 126.5×126.5 mm2. The gas filling is pure isobutane at NTP. The chamber operates without breakdown up to the electric field of 60 kV/cm. The PPC has a very fast response, and a time resolution of a few nanoseconds. The detection efficiency is close to unity. No saturation effects were observed for collected charges up to 1 pC. Results of the scanning of the electron and hadron shower development, using the prototype detector plane, are presented.

The xenon olive detector for the next generation colliders

Abstract We propose a fast detector with high resolution and fine granularity, consisting of a xenon electromagnetic shower counter and a TMS-uranium hadron calorimeter. Both are linear in energy, insensitive to radiation damage and have good spatial resolution in 3-dimensional space in order to measure di-electron and di-jet masses at the next generation high luminosity colliders.

The performance of a uranium gas sampling calorimeter

Abstract The performance of a uranium gas sampling hadron calorimeter is described. It has been observed that the hydrogen content of the gas mixture plays an important role in defining the behaviour of this type of calorimeter. The low-energy neutrons emerging from a hadron cascade are detected much more efficiently in a hydrogenous gas; thus leakage or containment of these neutrons becomes an important feature of the calorimeter setup.

Test of prototype hadron calorimeter for the L3 experiment

Abstract A fine sampling, tracking hadron calorimeter operating with limited streamer tubes and using a copper absorber has been tested with pions from 1 to 10 GeV/c. The energy resolution measured is consistent with the one expected from empirical formulae obtained for scintillator calorimeters, thus demonstrating that streamer tubes bring little or no loss in resolution. Our laboratory tests have demonstrated that chambers using tubes as small as 3.5 × 4.5 mm2 can operate satisfactorily in limited streamer mode.

Measurement ofπ0production at large transverse momentum inπ−p,π+p, andppcollisions at 300 GeV/c

Cross sections for inclusive ..pi../sup 0/ production at large transverse momentum p/sub T/ were measured in ..pi../sup -/p, ..pi../sup +/p, and pp collisions at 300 GeV/c. The cross-section ratio sigma(..pi../sup -/p..--> pi../sup 0/X)/sigma(..pi../sup +/p..--> pi../sup 0/X) was found to be consistent with unity in the p/sub T/ region of 1 to 5 GeV/c. The cross-section ratio sigma(..pi../sup +/p..--> pi../sup 0/X)/sigma(pp..--> pi../sup 0/X) however is growing with increasing p/sub T/ and increasing ..pi../sup 0/ c.m.-system rapidity in agreement with parton-model expectations, where the partons in the pions have on average higher momenta than in the proton.

The self-quenching streamer discharge in ArCO2 mixtures

Abstract Systematical investigations of the characteristics of the self-quenching streamer discharge and the ageing effects in Ar/CO 2 are presented. The cell size cross section, the high voltage, the wire diameter and the gas mixture ratio have been varied.

Measurement of np elastic scattering at high energies and very small momentum transfers

Abstract The np elastic differential cross section has been measured for incident neutron momenta 100–400 GeV/ c in the | t | range 6 · 10 −6 − 5 · 10 −1 (GeV/ c ) 2 . The np data of this experiment provide a first direct measurement of the hadronic amplitude for | t | −2 (GeV/ c ) 2 , which is consistent with the extrapolations from higher | t | values. Our data for | t | −4 (GeV/ c ) 2 are consistent with a rise which can be attributed to Schwinger scattering, caused by the interaction of the neutron magnetic moment with the proton.

Calorimeter tests with liquid ionization chambers

Abstract Configurations of sampling calorimeters with iron, lead and uranium as absorbers have been investigated using liquid ionization chambers as active elements. As liquid tetramethylsilane has been used. Results of beam tests with electrons, pions and muons in the energy range of 2 to 6 GeV are presented and compared with Monte Carlo simulations. In particular the questions regarding which configuration can compensate and the separation of sampling from intrinsic fluctuations have been studied.

Study of the performance of scintillating tiles with WLS fiber readout

We studied the characteristics of scintillating tiles with wavelength shifting fiber readout. The focus of this work has been directed toward the design and development of the Scintillating Barrel Calorimeter - the copper-scintillator tail catcher device - for the GEM detector at the SSC. However, these studies are applicable as well to the design of the hadron calorimeter for the Compact Muon Solenoid detector proposed for the Large Hadron Collider at CERN. We report on the results of light yield, response uniformity and timing measurements for tile-fiber configurations.<<ETX>>